Various structures are provided in a structural object such as a vehicle. Out of the structures, for example, for an in-vehicle camera, a vehicle lamp or a rearview mirror, it is desirable to remove foreign material such as moisture, dirt and dust in order to ensure good visibility. For example, the in-vehicle camera is utilized as a device for displaying a video on a display in order to check the rear of the vehicle or to check a position on the outside of the vehicle, which is hardly visible to a driver. An imaging unit of the in-vehicle camera is often contaminated by mud scattered by the driving of the vehicle or water droplets attached during rainy weather driving or the like. Thus, the video displayed on the display is blurred, which may cause a problem of interfering the checking.
In order to prevent occurrence of such a problem, for example, there is a foreign material removal device for removing foreign material such as moisture, mud and dirt attached to the imaging unit of the in-vehicle camera by injecting high-pressure air from a nozzle to the in-vehicle camera (e.g., see Patent Document 1).
In the foreign material removal device disclosed in Patent Document 1, high-pressure air from a compressed air generation unit is injected to the imaging unit to blow-off the mud and water droplets, thereby removing the contamination of the imaging unit.
The foreign material removal device for removing the contamination of the imaging unit by such compressed air has an advantage such that a liquid storage tank is not required and the injected liquid does not remain on the imaging unit, as compared with a foreign material removal device for removing the contamination by injecting high-pressure liquid such as water.